AZOO Aquarium CO2 Pressure Regulator Magnetic Valve with Option: Bubble Counter ; Stainless Steel Check Valve ; 10FT Silicone CO2 Proof Tubing (4/6mm) AZOO CO2 Pressure Regulator With Magnetic ValveX1 Bubble Counter (inside within CHECK VALVE) X1 10FT Silicone CO2 Proof Tubing (4/6mm)X1 STAINLESS STEEL CHECK VALVE X1 (CO2 bottle is not included)